Recently, as the use of various smart devices and high-resolution large screens as well as televisions has increased, the types of display devices have been diversified. In particular, a variety of flat panel displays (FPDs) have been developed which may further reduce the weight and volume than a so-called cathode ray tube (CRT). Specifically, flat panel displays, such as liquid crystal displays (LCDs), thin film transistor-liquid crystal displays (TFT-LCDs), plasma display panels (PDPs), and electroluminescence devices have attracted attention.
The electroluminescence devices may be classified into an inorganic light emitting diode and an organic light emitting diode (OLED) according to a material of an emitting layer. The OLED is a self-luminous organic material that emits light by itself by using an electroluminescence phenomenon that light is emitted when a current flows through a fluorescent organic compound. The OLED can be driven at a low voltage and made light and thin. Additionally, since each device is a luminous type that emits light, light is adjusted by changing a current flowing through each device. Thus, a backlight is not required. An OLED display device implemented with such OLEDs has advantages such as a fast response time, high image quality, high luminescent efficiency, an ultra-thin structure, and a wide viewing angle.
Due to the above advantages, the prospect of the OLED display device is bright, and the demand for the OLED display device is increasing. In the OLED display device, since each of elements of the OLED display device emits light, the elements may be different from each other in frequency of use and thus be different from each other in lifetime. For example, a logo included the broadcast content, an item on a menu screen, or the like is fixed to a specific position on the screen and continuously displayed.
In addition, the logo or item may have relatively high brightness in terms of visibility. In this instance, an element disposed on an area on which the logo or item is displayed may continuously emit light having the high brightness and thus be significantly reduced in lifetime when compared with elements disposed on other areas. When the element included in the area is significantly reduced in lifetime, the light emitted from the element may be reduced in brightness. As a result, an afterimage may occur due to a difference in brightness between the areas on a specific screen, and thus, the user may feel inconvenience when viewing an image through the OLED display device.